Fix -fsanitize=bool -fnon-call-exceptions (PR sanitizer/63913)

Hi!

This patch fixes instrumentation of bool/enum loads if they could
throw.  We want to keep the EH on the load, and push
further statements on the fallthru edge.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2014-11-18  Jakub Jelinek  <jakub@redhat.com>

	PR sanitizer/63913
	* ubsan.c: Include tree-eh.h.
	(instrument_bool_enum_load): Handle loads that can throw.

	* g++.dg/ubsan/pr63913.C: New test.


	Jakub

On Tue, 18 Nov 2014, Jakub Jelinek wrote:

> Hi!
> 
> This patch fixes instrumentation of bool/enum loads if they could
> throw.  We want to keep the EH on the load, and push
> further statements on the fallthru edge.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
> 
> 2014-11-18  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR sanitizer/63913
> 	* ubsan.c: Include tree-eh.h.
> 	(instrument_bool_enum_load): Handle loads that can throw.
> 
> 	* g++.dg/ubsan/pr63913.C: New test.
> 
> --- gcc/ubsan.c.jj	2014-11-14 15:11:49.000000000 +0100
> +++ gcc/ubsan.c	2014-11-18 09:29:20.409209556 +0100
> @@ -67,6 +67,7 @@ along with GCC; see the file COPYING3.
>  #include "dfp.h"
>  #include "builtins.h"
>  #include "tree-object-size.h"
> +#include "tree-eh.h"
>  
>  /* Map from a tree to a VAR_DECL tree.  */
>  
> @@ -1135,7 +1136,9 @@ instrument_bool_enum_load (gimple_stmt_i
>        || TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
>      return;
>  
> +  bool can_throw = stmt_could_throw_p (stmt);
>    location_t loc = gimple_location (stmt);
> +  tree lhs = gimple_assign_lhs (stmt);
>    tree ptype = build_pointer_type (TREE_TYPE (rhs));
>    tree atype = reference_alias_ptr_type (rhs);
>    gimple g = gimple_build_assign (make_ssa_name (ptype, NULL),
> @@ -1145,9 +1148,24 @@ instrument_bool_enum_load (gimple_stmt_i
>    tree mem = build2 (MEM_REF, utype, gimple_assign_lhs (g),
>  		     build_int_cst (atype, 0));
>    tree urhs = make_ssa_name (utype, NULL);
> -  g = gimple_build_assign (urhs, mem);
> -  gimple_set_location (g, loc);
> -  gsi_insert_before (gsi, g, GSI_SAME_STMT);
> +  if (can_throw)
> +    {
> +      gimple_assign_set_lhs (stmt, urhs);
> +      g = gimple_build_assign_with_ops (NOP_EXPR, lhs, urhs, NULL_TREE);
> +      gimple_set_location (g, loc);
> +      edge e = find_fallthru_edge (gimple_bb (stmt)->succs);
> +      gsi_insert_on_edge_immediate (e, g);
> +      gimple_assign_set_rhs_with_ops (gsi, MEM_REF, mem, NULL_TREE);

Please use gimple_assign_set_rhs_from_tree for single-rhs trees.

Ok with that change.

Thanks,
RIchard.

> +      update_stmt (stmt);
> +      *gsi = gsi_for_stmt (g);
> +      g = stmt;
> +    }
> +  else
> +    {
> +      g = gimple_build_assign (urhs, mem);
> +      gimple_set_location (g, loc);
> +      gsi_insert_before (gsi, g, GSI_SAME_STMT);
> +    }
>    minv = fold_convert (utype, minv);
>    maxv = fold_convert (utype, maxv);
>    if (!integer_zerop (minv))
> @@ -1169,8 +1187,11 @@ instrument_bool_enum_load (gimple_stmt_i
>    gimple_set_location (g, loc);
>    gsi_insert_after (gsi, g, GSI_NEW_STMT);
>  
> -  gimple_assign_set_rhs_with_ops (&gsi2, NOP_EXPR, urhs, NULL_TREE);
> -  update_stmt (stmt);
> +  if (!can_throw)
> +    {
> +      gimple_assign_set_rhs_with_ops (&gsi2, NOP_EXPR, urhs, NULL_TREE);
> +      update_stmt (stmt);
> +    }
>  
>    gsi2 = gsi_after_labels (then_bb);
>    if (flag_sanitize_undefined_trap_on_error)
> --- gcc/testsuite/g++.dg/ubsan/pr63913.C.jj	2014-11-18 09:34:10.603981487 +0100
> +++ gcc/testsuite/g++.dg/ubsan/pr63913.C	2014-11-18 09:33:47.000000000 +0100
> @@ -0,0 +1,12 @@
> +// PR sanitizer/63913
> +// { dg-do compile }
> +// { dg-options "-fsanitize=bool -fnon-call-exceptions" }
> +
> +struct B { B (); ~B (); };
> +
> +double
> +foo (bool *x)
> +{
> +  B b;
> +  return *x;
> +}
> 
> 	Jakub
> 
>